The ets gene family consists of a group of genes which are highly homologous to the 3' domain of the oncogene carried by the avian acute leukemia virus, E26. A peptide antibody corresponding to a hydrophilic and highly conserved 3' amino acid sequence of the human ets-2 protein was shown to specifically react with all known ets proteins (p135 v-ets. ets-1, ets-2, erg-1, erg-2), as well as several other uncharacterized ets-related antigens. The ets-2 protein was identified by use of monoclonal antibodies prepared against a bacterially expressed ets-2 protein. The ets-2 protein was shown to have several properties in common with other known nuclear oncogenes, including low abundance, fast turnover, nuclear localization and response to mitogenic stimuli. By contrast, the ets-1 protein is a cytoplasmic phosphoprotein. Two-dimensional gel electrophoresis of these proteins show their negative charge with an apparent isoelectric point of less than pH 6.0.